In order to provide integrated circuits (ICs) with increased performance, the characteristic dimensions of devices and spacing on the ICs continue to be decreased. Fabrication of such devices often requires the deposition of dielectric materials into features patterned into layers of material on silicon substrates. In most cases, it is important that the dielectric material completely fill such features. Filling such narrow features, so-called gap filling, places stringent requirements on materials used, for example, for pre-metal dielectric (PMD) applications. The pre-metal dielectric layer on an integrated circuit isolates structures electrically from metal interconnect layers and isolates them electrically from contaminant mobile ions that degrade electrical performance. PMD layers may require filling narrow gaps having aspect ratios (that is the ratio of depth to width), of five or greater. Dielectric films play an important role in the fabrication of semiconductor devices. It is therefore desirable to have improved processes for the deposition of dielectric films.